Method of treating a substrate wherein the flow rates of the treatment gases are equal

ABSTRACT

A method of treating a substrate with substantially equal flow rates of treatment gases in a treatment chamber containing the substrate. Because the times during which the treatment gases pass through pipes are controlled, even when the flow rates of the treatment gases differ appreciably, the impurity concentration in a film near the interface between the substrate and the film reaches a desired concentration. Also, when the times during which the treatment gases pass through the pipes are short, the treatment gases are unlikely to adhere to the walls of the pipes. It is thus possible to reduce the frequency of dummy runs.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of treating a substrate and,more particularly, to a method of treating a substrate by using two ormore gases whose flow rates differ appreciably.

2. Description of the Related Art

FIG. 7 is a schematic view showing conventional CVD equipment. Thestructure of the conventional CVD equipment will be described withreference to FIG. 7.

The CVD equipment has a chamber 1 and a gas introducing pipe 7. Asusceptor 3 is placed in the chamber 1. A semiconductor substrate 5rests on the main surface of the susceptor 3. The gas introducing pipe 7is arranged in the chamber 1, and extends from the inside of the chamber1 to the outside of the chamber 1. Gases used for forming a thin filmare fed into the chamber 1 via a terminal end 15 of the gas introducingpipe 7. A gas outlet pipe 9 also extends from the inside to the outsideof the chamber 1. The gases which have been fed into the chamber 1 aredischarged through the gas outlet pipe 9.

The gas introducing pipe 7 is branched at a diverging section 19 into anO₂ gas introducing pipe 20a, a SiH₄ gas introducing pipe 20b, a PH₃ gasintroducing pipe 20c, and a B₂ H₆ gas introducing pipe 20d. When a PSG(phosphosilicate glass) film is formed on the substrate 5, O₂ gas, SiH₄gas and PH₃ gas are utilized. On the other hand, when a BPSG(boro-phospho silicate glass) film is formed on the substrate 5, O₂ gas,SiH₄ gas, PH₃ gas, and B₂ H₆ gas are utilized. The O₂ gas introducingpipe 20a, the SiH₄ gas introducing pipe 20b, the PH₃ gas introducingpipe 20c, and the B₂ H₆ gas introducing pipe 20d are respectivelyprovided with mass flow controllers (MFCs) 17a, 17b, 17c, and 17d. TheseMFCs 17a, 17b, 17c, and 17d control the flow rates of the gases.

A valve 11 is attached to the gas introducing pipe 7 between a terminalend 15 of the pipe 7 in the chamber 1 and the diverging section 19. AnO₂ gas-containing cylinder is affixed to an initial end 13a of the O₂gas introducing pipe 20a; a SiH₄ gas-containing cylinder is affixed toan initial end 13b of the SiH₄ gas introducing pipe 20b; a PH₃gas-containing cylinder is affixed to an initial end 13c of the PH₃ gasintroducing pipe 20c; and a B₂ H₆ gas-containing cylinder is affixed toan initial end 13d of the B₂ H₆ gas introducing pipe 20d. Valves 52a-52dare affixed between the initial ends 13a-13d and the gas cylinders.

The longitudinal sectional areas of the hollow portions of the gasintroducing pipe 7, the O₂ gas introducing pipe 20a, the SiH₄ gasintroducing pipe 20b, the PH₃ gas introducing pipe 20c, and of the B₂ H₆gas introducing pipe 20d are all the same. The distances between theinitial end 13a of the O₂ gas introducing pipe, 20a and the terminal end15 of the gas introducing pipe 7 the initial end 13b of the SiH₄ gasintroducing pipe 20b and the terminal end 15 of the gas introducing pipe7, the initial end 13c of the PH₃ gas introducing pipe 20c and theterminal end 15 of the gas introducing pipe 7, and the initial end 13dof the B₂ H₆ gas introducing pipe 20d and the terminal end 15 of the gasintroducing pipe 7, are all substantially the same.

The operation of the conventional CVD equipment will be explained withreference to FIG. 7. First, the inside of the chamber 1 is filled withN₂ gas. The N₂ gas is fed into the chamber 1 through a gas pipe which isnot shown. The semiconductor substrate 5 placed on the main surface ofthe susceptor 3. The valve 11 is opened to feed the O₂ gas, SiH₄ gas,PH₃ gas, and the B₂ H₆ gas to the O₂ gas introducing pipe 20a, the SiH₄gas introducing pipe 20b, the PH₃ gas introducing pipe 20c, and the B₂H₆ gas introducing pipe 20d, respectively. The O₂ gas, SiH₄ gas, PH₃gas, and the B₂ H₆ are fed into the chamber 1 via the terminal end 15 ofthe gas introducing pipe 7. Thus, a BPSG film is formed on the mainsurface of the semiconductor substrate 5. Gas which has not been usedfor the reaction is discharged outside the chamber 1 through the gasoutlet pipe 9.

For example, when a PSG film is formed, the flow rate of the O₂ gas is2000 cc/min; that of the SiH₄ gas is 50 cc/min; and that of PH₃ gas is 2cc/min. The flow rate of the SiH₄ gas appreciably differs from that ofthe PH₃ gas. Consequently, there is a marked difference between the timerequired for the SiH₄ gas to reach the inside of the chamber 1 after thefeeding of it has begun, and the time required for the PH₃ gas to reachthe inside of the chamber 1 after the feeding of it has begun. Thisresults in a problem in that the concentration of P in the PSG film nearthe interface between the semiconductor substrate 5 and the PSG filmdoes not reach a desired concentration.

Moreover, because PH₃ gas adheres to the inner wall of a pipe, theamount of the PH₃ gas adhering to the inner wall of the pipes must bemade equal to the amount of the PH₃ gas not adhering to the inner wallof the pipe before the concentration of P in a PSG film can reach adesired concentration. This leads to a problem in that it is necessaryto form a thin film, one to five times, in order to render the amount ofof the PH₃ gas adhering to the inner wall of the pipe equal to theamount of the PH₃ gas not adhering to the inner wall of the pipe. Such aprocess for forming a thin film is referred to as a dummy run.

SUMMARY OF THE INVENTION

The present invention has been accomplished in order to solve the aboveproblems. Accordingly, the object of the invention is to provide amethod of treating a substrate in which the impurity concentration in afilm near the interface between the substrate and the film can reach adesired concentration, and in which the frequency of dummy runs can bereduced.

In order to achieve the above object, according to one aspect of theinvention, there is provided a method of treating a substrate comprisingthe steps of: housing a substrate in a treatment chamber; controlling aplurality of treatment gases so as to make the flow rates of thetreatment gases equal when the treatment gases are being introduced intothe treatment chamber; and treating the substrate with the treatmentgases.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration showing CVD equipment which is usedfor carrying out a first embodiment of the present invention;

FIG. 2 is a graph of the relationship between position and impurityconcentration in a thin film formed using the first embodiment of theinvention;

FIG. 3 is a graph of the relationship between position and impurityconcentration in a thin film, formed by a conventional method;

FIG. 4 is a graph showing the relationship between the number of timesthin films are formed using the first embodiment of the invention andimpurity concentration in the films;

FIG. 5 is a graph showing the relationship between the number of timesthin films are formed using the conventional method and impurityconcentration in the films;

FIG. 6 is a schematic illustration showing CVD equipment which is usedfor carrying out a second embodiment of this invention; and

FIG. 7 is a schematic representation showing conventional CVD equipment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

FIG. 1 is a schematic illustration showing CVD equipment which is usedfor carrying out the first embodiment of a method of treating asubstrate in accordance with the present invention. The construction ofthe CVD equipment shown in FIG. 1 will be described.

A susceptor 23 is placed inside a chamber 21. A semiconductor substrate25 is disposed on the main surface of the susceptor 23. A gasintroducing pipe 27 extends from the inside of the chamber 21 to theoutside of the chamber 21. A gas outlet pipe 41 also extends from theinside of the chamber 21 to the outside of the chamber 21.

The gas introducing pipe 27 is branched at a diverging section 49 intoan O₂ gas introducing pipe 29, a SiH₄ gas introducing pipe 31, a PH₃ gasintroducing pipe 33, and a B₂ H₆ gas introducing pipe 35. A valve 47 isattached to the gas introducing pipe 27 between a terminal end 43 of thepipe 27 in the chamber 21 and the diverging section 49.

The O₂ gas introducing pipe 29, the SiH₄ gas introducing pipe 31, thePH₃ gas introducing pipe 33, and the B₂ H₆ gas introducing pipe 35 arerespectively provided with mass flow controllers (MFCs) 39a, 39c, 39e,and 39g. These MFCs control the flow rates of gases.

A N₂ gas introducing pipe 37a is branched off from the O₂ gasintroducing pipe 29. A mass flow controller 39b is attached to the N₂gas introducing pipe 37a. A N₂ gas introducing pipe 37b is branched offfrom the SiH₄ gas introducing pipe 31. A mass flow controller 39d isattached to the N₂ gas introducing pipe 37b. A N₂ gas introducing pipe37c is branched off from the PH₃ gas introducing pipe 33. A mass flowcontroller 39f is attached to the N₂ gas introducing pipe 37c. A N₂ gasintroducing pipe 37d is branched off from the B₂ H₆ gas introducing pipe35. A mass flow controller 39h is attached to the N₂ gas introducingpipe 37d. Valves 50a-50h are affixed between initial ends 45a-45h andgas cylinders (not shown).

The distances between the initial end 45a of the O₂ gas introducing pipe29 and the terminal end 43, the initial end 45b of the N₂ gasintroducing pipe 37a and the terminal end 43, the initial end 45c of theSiH₄ gas introducing pipe 31 and the terminal end 43, the initial end45d of the N₂ gas introducing pipe 37b and the terminal end 43, theinitial end 45e of the PH₃ gas introducing pipe 33 and the terminal end43, the initial end 45f of the N₂ gas introducing pipe 37c and theterminal end 43, the initial end 45g of the B₂ H₆ gas introducing pipe35 and the terminal end 43, and the initial end 45h of the N₂ gasintroducing pipe 37d and the terminal end 43 are all substantially thesame. Also, the longitudinal sectional areas of the hollow portions ofthe gas introducing pipe 27, the O₂ gas introducing pipe 29, the SiH₄gas introducing pipe 31, the PH₃ gas introducing pipe 33, the B₂ H₆ gasintroducing pipe 35, and of the N₂ gas introducing pipes 37a, 37b, 37cand 37d are all the same.

For example, for the following, let it be assumed that the longitudinalsectional area of the hollow portion of each pipe is 0.3 cm², and thatthe distance between the initial end of each pipe and the terminal end43 is 200 cm. Then, when the flow rate of the O₂ gas is 1000 cc/min, theflow rate of the SiH₄ gas is 100 cc/min, and the flow rate of the PH₃gas is 10 cc/min, when a PSG film is formed, the times during which thegases pass through the pipes are as follows:

0.06 min for the O₂ gas,

0.6 min for the SiH₄ gas, and

6 min for the PH₃ gas.

In the first embodiment, the flow rate of the gas passing through the O₂gas introducing pipe 29, the flow rate of the gas passing through theSiH₄ gas introducing pipe 31, and the flow rate of the gas passingthrough the PH₃ gas introducing pipe 33 are made equal by feeding 900cc/min of the N₂ gas into the N₂ gas introducing pipe 37b, and 990cc/min of the N₂ gas into the N₂ gas introducing pipe 37c. The timesduring which the O₂ gas, the SiH₄ gas, and the PH₃ gas pass through thepipes are thus made equal. In other words, in the first embodiment, inorder to control the times during which the gases pass through thepipes, N₂ gas is fed into the N₂ gas introducing pipes 37a, 37b, 37c,and 37d.

The first embodiment of the present invention will be described below inmore detail. First, the inside of the chamber 21 was filled with N₂ gas.The N₂ gas is then fed into the chamber 21 through a gas pipe which isnot shown. The semiconductor substrate 25 was disposed on the mainsurface of the susceptor 23, and the temperature of the semiconductorsubstrate 25 was raised to a temperature at which a PSG film is formed.The valve 47 was opened to feed 900 cc/min of N₂ gas into the N₂ gasintroducing pipe 37b, and to feed 990 cc/min of N₂ gas into the N₂ gasintroducing pipe 37c. Thereafter, 1000 cc/min of O₂ gas was fed into theO₂ gas introducing pipe 29, 100 cc/min of SiH₄ gas was fed into the SiH₄gas introducing pipe 31, and 10 cc/min of PH₃ gas was fed into the PH₃gas introducing pipe 33. A PSG film was formed on the main surface ofthe semiconductor substrate 25. The concentration of P in this PSG filmwas 5%. Gas which has not been used for the reaction was dischargedthrough the gas outlet pipe 41. The concentration of P in the PSG filmwas measured, this film being formed through the use of the firstembodiment of the present invention. Various measuring methods, such asan XPS (X-ray photoelectro spectral analysis) and an SIMS (secondary ionmass spectrometric analysis), may be used.

FIG. 2 shows the measured results of the concentration of P. Theconcentration of P in a PSG film made according to this embodiment wasmeasured. FIG. 3 illustrates the measured results of the concentrationof P using the conventional method. Conditions under which the firstembodiment of the invention were carried out are the same as those forthe conventional example, except that N₂ gas is introduced. As shown inFIG. 2, in accordance with the first embodiment of the invention, theconcentration of P in the PSG film was 5% throughout the depth of thefilm, from the surface of the PSG film to the surface of the substrate25. On the other hand, as illustrated in FIG. 3, according to theconventional example, the concentration of P in the PSG film did notreach 5% in the proximity of the surface of the substrate 25.

Next, the first embodiment of the present invention was employed toclean the pipes, and a PSG film was formed on the semiconductorsubstrate 25. The semiconductor substrate 25 was then taken out of thechamber 1. Another semiconductor substrate was placed in the chamber 1,and the first embodiment of the invention was employed to form anotherPSG film on the semiconductor substrate. The above procedure wasrepeated seven times in succession. A measurement was made of theconcentration of P in every PSG film which was formed. FIG. 4 shows themeasured results of the concentration of P using the method of theinvention. The conventional method was then employed to perform the sameprocedure as above. FIG. 5 shows the results of the concentration of Pwhich were measured using the conventional method. The conditions underwhich a PSG film was formed in the first embodiment and the conventionalmethod were the same as above.

As is clear from FIG. 4, according to the first embodiment of thisinvention, it was found that the concentration of P in the PSG filmsnearly reaches the desirable concentration of 5% the first time, andthat it attained the desirable concentration the second time. On thecontrary, as shown in FIG. 5, in the conventional method, theconcentration of P in the PSG films did not reach the desiredconcentration until the PSG film was formed the sixth time. In the firstembodiment of the invention, since PH₃ and SiH₄ gases were diluted withN₂ gas, and since the flow velocity of these gases were caused toincrease, the PH₃ and SiH₄ gases did not adhere to the insides of thepipes. For this reason, the concentration of P in the PSG films reachedthe desired concentration from the first time. In accordance with thefirst embodiment of the invention, it is thus possible to eliminateunuseable wafers and to reduce the frequency of cleaning the pipes.

In the first embodiment of the present invention, the time during whichthe various raw gases pass through the pipes is controlled with N₂ gasso as to make the flow rates of the gases equal. This invention,however, is not limited to such control. The times during which thegases pass through the pipes may also be controlled by changing one ofthe following factors: the length of each pipe, the longitudinalsectional area of the hollow portion of each pipe, or the concentrationof each gas. The times may also be controlled by changing two or more ofthe above factors at the same time.

Though N₂ gas is employed in the first embodiment of the invention, theinvention is not limited to N₂ gas. Any gas, such as an inert gas, mayalso be employed so long as it exhibits inert characteristics at thetemperature at which a thin film is formed.

Furthermore, although a CVD process is utilized in the first embodimentof the invention, the invention is not limited to such a process. Thisinvention may also be applied in a case when etching is performed bygases, the flow rates of these gases being greatly different.

Second Embodiment

A second embodiment of the invention will now be described. FIG. 6 is aschematic illustration showing CVD equipment which is used for carryingout the second embodiment of the invention. The construction of the CVDequipment shown in FIG. 6 will be explained.

A susceptor 63 is placed inside a chamber 61. A semiconductor substrate65 is disposed on the main surface of the susceptor 63. A gasintroducing pipe 67 extends from the inside of the chamber 61 to theoutside of the chamber 61. A gas outlet pipe 85a also extends from theinside of the chamber 61 to the outside of the chamber 61.

The gas introducing pipe 67 is branched at a diverging section 69 intoan O₂ gas introducing pipe 71, a pipe 73 for Si-containing gas, a pipe75 for P-containing gas, and a pipe 77 for B-containing gas. The O₂ gasintroducing pipe 71, the pipe 73 for Si-containing gas, the pipe 75 forP-containing gas, and the pipe 77 for B-containing gas are respectivelyprovided with mass flow controllers (MFCs) 81a, 81d, 81f, and 81h.Valves 51a-51h are affixed between initial ends 55a-55h and gascylinders (not shown).

N₂ gas introducing pipes 79a, 79b, 79c, and 79d are respectivelyconnected to the O₂ gas introducing pipe 71, the pipe 73 forSi-containing gas, the pipe 75 for P-containing gas, and the pipe 77 forB-containing gas. The time during which the gases pass through the pipesis controlled by feeding the N₂ gas into the N₂ gas introducing pipes79a, 79b, 79c, and 79d. Mass flow controllers (MFCs) 81b, 81c, 81e, and81g are respectively affixed to these N₂ gas introducing pipes 79a, 79b,79c, and 79d.

The pipe 73 for Si-containing gas runs through a bubbling chamber 83a inwhich a liquid TEOS (Silicon tetraethylorthosilicate:Si (OC₂ H₅)₄) 89 iscontained. The pipe 75 for P-containing gas runs through a bubblingchamber 83b, in which a liquid TMPO (Phosphorus trimethyloxide:PO(OCH₃)₃) 91 is contained. The pipe 77 for B-containing gas runsthrough a bubbling chamber 83c, in which a liquid TEB (Triethyl Borate:B (OC₂ H₅)₃) 93 is contained.

In the CVD equipment constructed in this manner, a liquid such as TEOSis bubbled with N₂ gas, whereby the gas evolved is used to formed a thinfilm on the semiconductor substrate. By using such CVD equipment, thinfilms may be obtained whose coverage is better than that of thin filmsobtained by the conventional CVD equipment.

For example, when a BPSG film is formed (the concentration of B in thisfilm being 5 mole %, and the concentration of P in the film being 5 mole%), the flow rate of the N₂ gas which is fed into the pipe 73 forSi-containing gas, the flow rate of the N₂ gas which is fed into thepipe 75 for P-containing gas, and the flow rate of the N₂ gas which isfed into the pipe 77 for B-containing gas, are as follows:

First, the number of moles of TEOS, the number of moles of TMPO, and thenumber of moles of TEB which are respectively required for preparing onemole of SiO₂ one mole of P₂ O₅, and one mole of B₂ O₃ are determined.

    Si (OC.sub.2 H.sub.5).sub.4 →SiO.sub.2 +2C.sub.2 H.sub.5 OC.sub.2 H.sub.5

Thus, one mole of SiO₂ can be prepared with one mole of TEOS.

    2PO (OCH.sub.3).sub.3 →P.sub.2 O.sub.5 +3CH.sub.3 OCH.sub.3

Thus, one mole of P₂ O₅ can be prepared with two moles of TMPO.

    2B (OC.sub.2 H.sub.5).sub.3 →B.sub.2 O.sub.3 +3C.sub.2 H.sub.5 OC.sub.2 H.sub.5

Thus, one mole of B₂ O₃ can be prepared with two moles of TEB.

Hence, SiO₂ : P₂ O₅ : B₂ O₃ =90 mole %: 5 mole %: 5 mole %

Therefore,

TEOS: TMPO: TEB=90: 10: 10 =9: 1: 1

In a gaseous state, since a molar ratio is a flow rate,

    TEOS gas TMPO gas: TEB gas=9: 1: 1                         (1)

The vapor pressures of TEOS, TMPO, and TEB at a temperature of t°C. areexpressed as follows:

    TEOS: log.sub.10 P=9.651-1817.5/(t+225.56)                 . . . (2)

    TEOS: log.sub.10 P=10.170-2416/(t+273.15)                  . . . (3)

    TEOS: log.sub.10 P=10.267-2061/(t+273.15)                  . . . (4)

where P is vapor pressure (Pa), one atmospheric pressure being 101325Pa, whereas t is absolute temperature. The above equations are quotedfrom a gas catalog issued by Chemical Laboratory Co., Ltd. Aug. 4, 1989.

From equation (2), the vapor pressure of TEOS at 60° C. is obtained asfollows:

    P≈1933 Pa=14.5 mm Hg

Thus, the amount of TEOS gas evolved by bubbling TEOS at 60° C. with 3l/min of N₂ gas is as follows:

    (14.5 mm Hg/760 mm Hg)×3l/min=0.0572 l /min

Therefore, from equation (1), 0.00636 l /min of TMPO gas and of TEB gasmust be evolved. The flow rate of N₂ gas required for evolving 0.00636l/min of TMPO gas and of TEB gas is determined as follows:

As regards the flow rate of N₂ gas required for bubbling TMPO,

from equation (3), the vapor pressure of TMPO at 60° C. is 6.21 mm Hg,thus,

    0.00636 l/min=(6.21 mm Hg/760 mm Hg)×the flow rate of N.sub.2 gas l/min

hence, the flow rate of N₂ gas required for bubbling TMPO is 0.778l/min.

As regards the flow rate of N₂ gas required for bubbling TEB,

from equation (4), the vapor pressure of TEB at 60° C. is 90.3 mm Hg,thus,

    0.00636 l/min=(90.3 mm Hg/760 mm Hg)×the flow rate of N.sub.2 gas l/min

therefore, the flow rate of N₂ gas required for bubbling TMPO is 0.0535l/min.

Hence, the flow rate of N₂ gas to be fed into the pipe 73 forSi-containing gas is 3 l/min; the flow rate of N₂ gas to be fed into thepipe 75 for P-containing gas is 0.778 l/min; and the flow rate of N₂ gasto be fed into the pipe 77 for B-containing gas is 0.0535 l/min. Thus,the flow rate of the gas passing through the respective pipes differsmarkedly.

To solve the above problem, in the second embodiment, the following twomethods were employed. The first method will be described.

In this method, the flow rates of gas, which passes through the pipe 73for Si-containing gas, the pipe 75 for P-containing gas, and the pipe 77for B-containing gas, are made equal by feeding N₂ gas into the N₂ gasintroducing pipes 79b, 79c, and 79d. In such a case, 0 l/min, 2.222l/min, and 2.9465 l/min of the N₂ gas are respectively fed into the N₂gas introducing pipes 79b, 79c, and 79d.

The second method is a method in which the vapor pressures of TEOS,TMPO, and of TEB are controlled, whereby the flow rates of N₂ gas usedfor bubbling are made equal. For instance, as explained above, theamount of TEOS gas, which is evolved by bubbling TEOS at 60° C. with 3l/min of N₂ gas, is 0.0572 l/min. Thus, it is necessary that 0.00636l/min of TMPO gas and of TEB gas be evolved. Since TEB is bubbled with 3l/min of N₂ gas, the vapor pressure V₁ of TMPO and the vapor pressure V₂of TEB are controlled as follows:

As regards TMPO,

    (V.sub.1 mm Hg/760 mm Hg)×3 l/min=0.00636 l/min,

so that V₁ is 1.61 mm Hg. When the temperature of TMPO is 35° C., thevapor pressure V₁ of TMPO assumes is 1.61 mm Hg from equation (3).

As regards TEB,

    (V.sub.2 mm Hg/760 mm Hg)×3 l/min=0.00636 l/min,

hence, V₂ is 1.61 mm Hg. When the temperature of TEB is -13.4° C., thevapor pressure V₂ of TEB is 1.61 mm Hg from equation (4).

The second embodiment of the present invention may also be applied in acase where TMOS, TPOS, DADBS, TMP, TMB, TPB, TBB, etc. are utilized toform thin films.

Further, an oxide film or a doped metal film such as p-doped polysiliconcan also be formed according to the present invention.

In the present invention, the times during which various gases passthrough pipes are so controlled that the flow rates of the gases areequal. Therefore, even when gases whose flow rates appreciably differare employed to form a thin film, the impurity concentration in a filmnear the interface between the thin film and the substrate can have adesired concentration. In addition, since the times during which gasespass through pipes are made short, the gases are unlikely to adhere tothe walls of the pipes, whereby the frequency of dummy runs can bedecreased. It is thus possible to increase the yield in manufacturingsemiconductor devices.

What is claimed is:
 1. A method of treating a substratecomprising:placing a substrate in a treatment chamber; separatelycontrolling the flow rates of each of a plurality of treatment gas flowsso that the respective flow rates of the treatment gas flows aresubstantially equal, each treatment gas flow including a respectivetreatment gas and at least one of the treatment gas flows including acarrier gas; mixing the plurality of treatment gas flows; introducingthe mixed plurality of treatment gas flows into the treatment chamber;and treating the substrate with the treatment gas flows introduced inthe treatment chamber.
 2. A method of treating a substrate as claimed inclaim 1 wherein each of the treatment gas flows includes a carrier gasand the respective treatment gas.
 3. A method of treating a substrate asclaimed in claim 1 including controlling the vapor pressure of at leastone treatment liquid, bubbling a carrier gas through the treatmentliquid to produce one of the treatment gas flows.
 4. A method oftreating a substrate as claimed in claim 1 wherein the substrate is asemiconductor substrate.
 5. A method of treating a substrate as claimedin claim 1 wherein the treatment gases are oxygen gas, silane gas, andphosphine gas to form a phospho-silicate glass film on the substrate. 6.A method of treating a substrate as claimed in claim 1 wherein thetreatment gases are oxygen gas, silane gas, phosphine gas, and boranegas for forming boro-phosphosilicate glass film on the substrate.
 7. Amethod of treating a substrate as claimed in claim 1 including formingan oxide film on the substrate.
 8. A method of treating a substrate asclaimed in claim 1 including forming a doped film on the substratesemiconductor.
 9. A method of treating a substrate as claimed in claim 8wherein the doped film is p-doped polysilicon.
 10. A method of treatinga substrate as claimed in claim 1 including selecting the carrier gasfrom the group consisting of nitrogen and inert gases.
 11. A method oftreating a substrate as claimed in claim 3 wherein the treatment liquidsare selected from the group consisting of tetraethylorthosilicate,phosphorus trimethyloxide, and triethyl borate.
 12. A method of treatinga substrate as claimed in claim 1 including chemical vapor deposition asthe treatment.
 13. A method of treating a substrate comprising:placing asubstrate in a treatment chamber; introducing a plurality of treatmentgases into respective pipes connected to sources of the respectivetreatment gases and to the treatment chamber; and controlling the timesthe respective treatment gases travel through the respective pipes fromthe respective sources to the treatment chamber so that the times aresubstantially the same for each of the treatment gases.
 14. A method oftreating a substrate as claimed in claim 13 including controlling thetimes the respective treatment gases travel through the respective pipeby adding a carrier gas at a controlled flow rate to at least one of thetreatment gases.
 15. A method of treating a substrate as claimed inclaim 13 including controlling the time a treatment gas derived from aliquid source travels through one of the pipes by controlling the flowrate of a carrier gas through the liquid source.
 16. A method oftreating a substrate as claimed in claim 13 including controlling thetime a treatment gas derived from a liquid source travels through one ofthe pipes by controlling the vapor pressure of the liquid source.
 17. Amethod of treating a substrate as claimed in claim 16 includingcontrolling the time the treatment gas derived from the liquid sourcetravels through one of the pipes by controlling the flow rate of acarrier gas flowing through the liquid source.